LuTiao Programming

Aug 20, 2026 · Backend Development

Recreating WeChat’s Unread Red Dot with Spring Boot: One lastReadSeq Handles 10,000 Messages

The article explains how to replace per‑message read flags with a single lastReadSeq column and an unreadCount cache, enabling efficient unread‑message tracking for large group chats and multi‑device synchronization in a Spring Boot chat system.